1. Field of Invention
The present invention relates to modular refractory fiber blanket furnace lining systems.
2. Description of Prior Art
Refractory fiber blankets made from refractory materials such as chromia-alumina-silica, alumina-silica compositions and zirconia compositions have become desirable as furnace insulation because of their ability to withstand high temperatures. The fiber blanket material has been attached in a layered construction arrangment to the furnace wall using attachment structure, as exemplified in U.S. Pat. Nos. 3,523,395 and 3,605,370.
Another approach has been to form modules or blocks of refractory fiber blanket material, as exemplified by U.S. Pat. Nos. 3,832,815 and 3,819,468.
However, in certain areas of the furnaces being insulated, problems were still present. In portions of some stacks and flues, as well as in convection sections of certain types of reformers, gas velocities often far exceed forty to eighty feet per second. Other examples of high temperature equipment are high temperature wind tunnels and mufflers or noise abatement systems for silencing jet engines and gas turbines during repair and maintenance. Gases at these velocities were capable of in effect picking away individual fiber elements from the blankets and thereby eroding the blanket, whether in a module or layered construction, during use.
Further, in areas of the furnaces near burners, or in "target" areas where high velocity burners impinged, flame erosion caused further problems. In addition to high velocity gas erosion, devitrification of the fibers by the flames made the fibers more easily erosible by the gases, further compounding the problem.
Other types of insulation structure, such as fibrous batting, in which the layers were bound together by glue, as exemplified by U.S. Pat. No. 2,454,175, were unsatisfactory for several reasons, for example, ease of installation and repair, cost of fabrication and inadequate ability to withstand high temperatures.